Cylinder relief valve for compressors



March 12, 1935. w. RAYMOND 1,994,179 I CYLINDER-,RELIEF VALVE FORCOMPRESSORS Filed June 5, 1930 Ill/11111111111112 mvEN'i'oR BY 17 WATTORNE -mally.-; ,h,

r And finally it is an" object of the-invention to Patented Mar. l2;I935 I f Lemmas RELIEF VALVE FOR YCQMPRESSORS war-a Raymond, IiastonQPaassignor to Penn- V sylvania Pump 5& Compressor Company,

- Easton, Pa., a corporation of Pennsylvania pp1i ati6n,mne 5, 1930,Serial No. 459,279

' ZGIaims (o1."137-- '-153) I I This invention relates toreliefvalvesand. particularly to a cylinder relief valve for 'ai-r and gascompressors. I, 7 "An object of the invention isto providean improvedform 'ofsrelief valve forcompres'sor cylindersadapted normally to beretained in closed for: retaining 'a cylinder relief valve in, its'closed position so that under; normal operationsathe combined action ofthefluid pressure and, spring will be csufiicient to retainithereliefzvalveiin its closed position, but: which, when pressure withinthe fiuidmeansis materially reduced, will permit the valve to open andallow airyor gas within the cylinder to escape without, beingcompressed.

. A still further object: of the invention to provide a relief valve forcompressors that willnbe held closedxduring nonnal operation ofthe-compressor but that willopen when the compressor is operating"unloaded and will return to. closed .position when the compressor-isagain operating noroperate a cylinder relief; valve directly; byvariationsin; pressure ;of *the air or, gas within the compressor intakeby simple, inexpensive means not easily put out of order and which has aminimum of operating parts. With these and other objects in view, myinvention includes the features of construction and operation set forthinfthe following specification I specification being relied upon forthat purpose;

In the drawing:

Figure 1 is a side elevation of a compressor cylinder provided with therelief valve forming the present invention attached thereto, and V Fig.2 is a longitudinal sectional view centrally through one of the reliefvalves. 7

In the above mentioned drawingI have shown but one embodiment of theinvention which is now deemed preferable, but it is to be underspondingrelief valves; being placed stood i that changes and modifica tions maybe made. within the scope of the appended claims withoutdeparting fromthe spirit of the inven: tion. 1 1

In the operation of compressors foraironother gases,it isusual toprovide some form of unloading mechanism enabling the compressorito-oper ate without delivery of additional compressed air or other gas;A common method Qfefiecting'this unloading of a compressor istoprovide'means for closing the intake passages to the cylinder so,thatno airor'gas may be drawn into the cylinder. il'he pres'surewithin thecylinder thus becomes greatly reduced and'the piston reciprocatesWithillytlfliS I reduced pressure. During the period of unloadedoperation the only air or gas compressed is that leaking past the valvesinto thecylinder," ,In op.-

crating compressors withthismethod of ,unloading,it isdesirable toprovide means for relieving the pressure within the cylinders whenever-;the terminal pressure becomes, excessive and alsoas soon as the intakevalve closes anda materially reduced pressure is produced within theintake Passage r The relief valve forming the present invention istherefore adapted for attachment toacompressor cylinder, one end of thereliefvalvebeing connected to the interior of the cylinder, correa O psit ends, of the compressor cylinders j 1 Referring more in detail tothe figures of the drawing, I provide a compressor cylinder 10 having anintake closing valve 11 forming a regulator or unloading means directlyattached to the compressor intake. This valve 11 is attached directly tothe intake connection 12 of the cylinder. As this form of intake closingvalve is old and well-known, it is not thought necessary to describe itin'detail. It will sufiice to state that this valve 11 may be completelyclosed when the air or gas has been compressed to a predeterminedpressure and may be again opened when the pressure is reduced andadditional air is desired;

Connected to the opposite ends of the cylinder 10 are the body members13 of the relief valves, these being similar in form and preferablyhaving a threaded opening 14 at one end enabling them to be connected asby a short length of pipe directly to an opening into the interior ofthe compressor cylinder 10.

Within this body member 13 is a valve 15 pressed normally against a seatformed within the body member 13so that when this valve 15 is closed airor gas cannot pass and escape to outer end of which engagesagainstitheinner;

end of the piston 16 also serves to hold the valve toward its seat. Theopening 19 within the head 18 as shown in Fig. 1, is. adapted't'o'b'econnected by suitable piping "22 to aportionof the compressorintake betweenthe cylinder 10 and theintakevalve 11.

Normally and with the compressor-operating under load, the pressurewithinthe intake passage's l'2 issubsta-ntially atmospheric, which pres--"siir'e is 'ex erted against the 'rfull' diameter? of the piston IG-bythe' connection 22 aiding the spring in maintaining the valve 15 towardits seat. s'oon,-however,"as the intake valve :11 operates 'to close theconnection to intake 1'2"arid 'a subatmospheric or sub -normal pressure:exists within the intake passage the pressure exerted aigainst thepiston l'fi 'ismaterially reduced. 'Thus reduced, the 'piston- 16 isdrawntoward the "head 1 8,'='tl'ius relieving-the valve 15'from any.pressure xcept -that of the light spring 21'forcing it t'oW'ardits-seat. The valve 15"theref ore; whenever there is any appreciablepressurewithin the end of fthe compressor' cylinder 10, opens' andallows thef air or'g'as to escape 'to atmosphere. Fr this purpose alateral opening 23 may be 'firb vfdd 'in' the body member '13 connectedas by FpipiiigZA- tO atmosphere. 'As' soon-as-the intake valve 11- againoperates to admit air o'r gas thtodgh iiitake 12 and atmospheric ornormal -"1n"ess'ure -again exists within the intake of the'o'rii'pres'sor the piston 16' is again forced fora wardly, thusreturning the valve 15 firmly against its' 'sat.

'Ihe relief 5 valve }1'5 "may also act to relive ext'rh'le pressures"within the cylinderIO "if such 'iices'sivepressure should exist at anytiine -diirin'g'"normal operation. To open'the valve 15'-'withatmospheric pressure being'ex'erted against -the piston 16 requires apressure within the compressor cylinder 10 suflicient to compresssprings 20 and 21 and allow the piston 16 and valve 15 to move from thepositions shown in Fig. 2.

In certain installations, as, for instance, when the cylinder 10 shownin the drawing is the'high pressure cylinder of a compressor,thespringiZO maYfbG OmittBd. iWiththe relief valve Lthus used: 7 theopening"19 may be connected to'a point in the compressor system withinwhich an inter-j;

mediate pressurernormally exists, such as a'niin ftrcoolenicll-i'sjsoonas the 'intake'is closed by the regulator or unloader valve 1 1, thepressure is reduced within, the -intercooler, thus relieving the piston1'6 "or .aportion of theipressure holding it-towardftheclosedgpositionof the valve 15;

What I claim is: r v 1.-'A cylinder relief valve for compressors;comprising in combination, a body member adapted for, connection to acylinder, a valve therein having a- 'cylindrical: guiding suriface= insaid body, meniberi and opening and closingia,

passage therethrough, a cylinden within -said body: member;aipi'ston'movable" Within isaidw'cyl- 7 inder "and acting-against saidzvalve, :said walve and piston :"being freelyfi laterally-.cadjiistable;;a :spring *housed within said lpistonaionnallyitorc'e ing said: pistonand valve in a-adirectionatoccloae saidipassagaea :spring housed withinsaid zval-ve and tending to force said valve from said piston andtowardits closedzposition; and'meansswhere by air may the exhausted:fromtsafd fcylinder; .1

2 3A cylinder relief iva'lv'e''f for'rcompressors :.:comprising :in:combination; a-ibody member :a'dapte'd ifOI ifconnection 'to a:cylinder, dad-valve therein havi'ng Ia icylindricalcguidingiisuriaceiin saidi'body membergandzopeningrand c1osing.a3pas-' sage:therethrou'gh: from :S&idconnection-mo at :mo'sphere,atcylind'er'wvithin saidrbody membenraehollowzpiston'movablewithinzsaidcylinderrhavvalve upon :its iplane end:surface nvvherebyisatd valve is free 'to adjju'st 'itselfj laterallyxfifsaid Zpisto'n, a spri'n'g housed within said pistonr norhausted fromsaidcylinder.. i wARD PRAYMQND- Vfingfiazplaneeridtsurfacearidcactingiagainst said-

